Hank: Are you like me? Do you sneeze when you are exposed to a bright light when you walk outside after being inside for along time or when you exit a tunnel? Well, 3/4 of you are thinking, "What the heck are you talking about? That can't possibly be a thing." But a quarter of you, including me, are like, "Yeah, totally, yes. Yes, that is me." It's called the "photic sneeze reflex," and we don't know exactly what causes it, but it's definitely a thing.

One idea is that the nerves in your face are getting their signals crossed between your eyes and your nose, so that your brain goes, "Ah! Bright light make nose itch! So, I should sneeze now." Scientists are actually trying to figure out right now if this reflex is genetic, and if so, what genes are involved, and what these genes do. The good news is that it seems to be entirely harmless; you just might want to have your sunglasses ready if you go through a lot of tunnels.

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